The effect of breast cancer screening is declining


By Søren R Christiansen, Philippe Autier, Henrik Støvring

The effect of breast cancer screening is declining

A new study raises the debate about the progressive decrease in the benefits of breast cancer screening which would be at a too low level compared to their consequences in terms of overdiagnosis and overtreatment.
Researchers from the University of Aarhus, Department of Public Health, Denmark, and the International Prevention Research Institute (IPRI), Lyon, France, are the authors of the study.
They state that breast cancer mortality has decreased over the past three decades due to improvements in patient management and better therapies, while the number of women needed to be invited to mammography screening in Denmark to prevent one cancer death in 10 years has doubled.

"As the beneficial effects of mammography screening declines ever more, we should consider abandoning the current mammography screening program with biennial mammograms for everyone aged 50-70. Perhaps a more targeted, high-risk screening strategy could be an alternative, if studies showed the strategy's beneficial effects," Støvring, associate professor in the department of public health at Aarhus University declared in an interview.

"I think we are approaching a point where just continuing might become untenable from an ethical point of view, as fewer and fewer women will experience gains due to screening (they would not die from breast cancer anyway due to improved treatment), but the number of women harmed due to overdiagnosis and overtreatment remains constant," he noted.

H.Støvring believes that for breast cancer the evidence for mammography screening is not convincing. He declared: "I think it is critical that we reassess screening programs as new evidence becomes available”. 

In conclusion, improvements in cancer therapy over the past 30 years have reduced mortality, which may erode the benefit-harm balance of mammography screening.

In addition, future improvements in the management of patients with breast cancer will increasingly reduce the benefit-risk ratio of screening.

The benefit of mammography in terms of reduced mortality declines while the harms such as overdiagnosis are unaffected. Screening leads to both overdiagnosis and overtreatment, which has a cost both on a human level and in terms of the economy.

Interview with the main author, June 24, 2022 by Helle Horskjær Hansen

Screening for breast cancer has a cost. This is shown by a Danish/Norwegian study that analysed 10,580 breast cancer deaths among Norwegian women aged 50 to 75 years. 
"The beneficial effect of screening is currently declining because the treatment of cancer is improving. Over the last 25 years, the mortality rate for breast cancer has been virtually halved," says Henrik Støvring, who is behind the study.
According to the researcher, the problem is that screenings lead to both overdiagnosis and overtreatment, which has a cost both on a human level and in terms of the economy. 

Overdiagnosis and overtreatment

When the screening was introduced, the assessment was that around twenty per cent of the deaths from breast cancer among those screened could be averted. While this corresponded to approximately 220 deaths a year in Denmark 25 years ago, today the number has been halved. 

The study shows that in 1996 it was necessary to invite 731 women to avoid a single breast cancer death in Norway, you would have to invite at least 1364 and probably closer to 3500 to achieve the same result in 2016. 
On the other hand, the adverse effects of screening are unchanged.

"One in five women aged 50-70, who is told they have breast cancer, has received a 'superfluous' diagnosis because of screening – without screening, they would never have noticed or felt that they had breast cancer during their lifetime," says the researcher. 

One in five corresponds to 900 women annually in Denmark. In addition, every year more than 5000 women are told that the screening has given rise to suspicion of breast cancer – a suspicion that later turns out to be incorrect.

Peaceful, small nodes – but in who?

Henrik Støvring notes that the result is not beneficial for the screening programmes.

According to the researcher, the challenge is that we are not currently able to tell the difference between the small cancer tumours that will kill you and those that will not.

Some of these small nodes are so peaceful or slow-growing that the woman would die a natural death with undetected breast cancer, if she had not been screened. But once a cancer node has been discovered, it must of course be treated, even though this was not necessary for some of the women – we just do not know who.

"The women who are invited to screening live longer because all breast cancer patients live longer, and because we have got better drugs, more effective chemotherapy, and because we now have cancer care pathways, which mean the healthcare system reacts faster than it did a decade ago,” says Henrik Støvring.

Abstract of the study


Søren R Christiansen, Philippe Autier, Henrik Støvring, Change in effectiveness of mammography screening with decreasing breast cancer mortality: a population-based study, European Journal of Public Health, 2022;, ckac047,


Reductions in breast cancer mortality observed over the last three decades are partly due to improved patient management, which may erode the benefit-harm balance of mammography screening.


We estimated the numbers of women needed to invite (NNI) to prevent one breast cancer death within 10 years. Four scenarios of screening effectiveness (5–20% mortality reduction) were applied on 10,580 breast cancer deaths among Norwegian women aged 50–75 years from 1986 to 2016. We used three scenarios of overdiagnosis (10–40% excess breast cancers during screening period) for estimating ratios of numbers of overdiagnosed breast cancers for each breast cancer death prevented.


Under the base case scenario of 20% breast cancer mortality reduction and 20% overdiagnosis, the NNI rose from 731 (95% CI: 644–830) women in 1996 to 1364 (95% CI: 1181–1577) women in 2016, while the number of women with overdiagnosed cancer for each breast cancer death prevented rose from 3.2 in 1996 to 5.4 in 2016. For a mortality reduction of 8.7%, the ratio of overdiagnosed breast cancers per breast cancer death prevented rose from 7.4 in 1996 to 14.0 in 2016. For a mortality reduction of 5%, the ratio rose from 12.8 in 1996 to 25.2 in 2016.


Due to increasingly potent therapeutic modalities, the benefit in terms of reduced breast cancer mortality declines while the harms, including overdiagnosis, are unaffected. Future improvements in breast cancer patient management will further deteriorate the benefit–harm ratio of screening.

Key points

Assuming a relative effect of mammography screening at 20% on breast cancer mortality, the number of women who needs to be invited to save one life has increased by 87% from 1996 to 2016. (Editor's note: this means that it is currently necessary to screen an ever increasing number of women in order to have a breast cancer death that would be prevented by screening, so it is more difficult to find a woman who has benefited from screening, while the adverse effects do not decrease (overdiagnosis)).

The number of women overdiagnosed with breast cancer per woman saved from dying of breast cancer has increased substantially from 1996 to 2016.

The deterioration in benefit-to-harm ratio of breast screening will continue due to steady improvement in therapies.

This study supports the need for re-evaluation of national screening programmes in high-income countries.


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“A cost both on a human level and in terms of the economy... “

...According to the lead author.

Another recent study raises the issue of additional costs associated with declining screening effectiveness:

In this paper, the authors exploit a natural experiment resulting from the phased geographic rollout of a national mammography screening programme in Ireland to examine the impact of screening on breast cancer outcomes from both a patient cohort and a population perspective. 

Ireland is one of the few countries where, for operational reasons, the rollout of screening has resulted in a cohort of unscreened women that has existed long enough to serve as an appropriate comparison group.

Using data from 33,722 breast cancer cases diagnosed between 1994 and 2011, the authors employ a difference-in-differences research design using ten-year follow-up data for cases diagnosed before and after the introduction of the programme in screened and unscreened regions. 

They conclude that, although the programme produced the intended intermediate effects on breast cancer presentation and incidence, these failed to translate into significant decreases in overall population-level mortality, though screening may have helped to reduce socioeconomic disparities in late stage breast cancer incidence.

Highlights of the study

  • Screening increased detection of asymptomatic and early stage cancers.
  • There was no significant effect on population breast cancer or all-cause mortality.
  • Screening may have reduced socioeconomic disparities in late stage incidence.
  • Results call in to question the overall effectiveness of this common intervention.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Evaluation of information on screening, the situation in Italy, French parallel, and hope…

Synthesis Dr. C.Bour, May 11, 2022

According to the authors of this Italian study published in BioMed Central (BMC, a scientific journal) on April 22, 2022, information about overdiagnosis showed a notable increase in 2021 compared with 2014. However, the frequency of this information in the documents aimed at women was still low, probably because it is both the most recent and harmful risk for women. Therefore, not all health operators are aware of overdiagnosis. If they are aware of it, they might avoid reporting the information in public documents for fear of dissuading women from undergoing screening. Moreover, many reports of overdiagnosis are unclear.

It is difficult not to find a parallel with the situation regarding information in France.

This situation of insufficient information for women persists for many reasons.

One of the most frequently reported justifications is that providing information on potential harms could reduce adherence to screening.

Method and results

As information provided to women on the benefit-risk balance is still highly biased, F. Atténa (Department of Experimental Medicine, University of Campania "Luigi Vanvitelli") and her collaborators have decided to evaluate documents addressed to the general female public and published on the Internet by the Italian national and regional public health services.

Information on false positives and false negatives, biopsy-proven false positives, interval cancer, overdiagnosis, radiation exposure, and mortality risk reduction was analyzed. In addition, quantitative data were investigated.

The 2021 situation was compared with the 2014 situation.

Overdiagnosis and biopsy-proven false-positive results were the least reported risks of screening (20.1% and 10.4%).
Compared to the 2014 information, the 2021 information showed some improvements. The most marked improvements concern overdiagnosis. The declarations of this adverse effect increased from 8.0 to 20.1%.
Concerning the number of false positives proven by biopsy, there is also an increase in the information from 1.4 to 10.4%.
But quantitative data remained scarce in 2021.

The authors conclude with the evidence of moderate improvements in information observed from 2014 to 2021.

However, information about breast cancer screening in materials for women published on Italian websites remains too sparse.

A previous shocking Italian study from 2020

A study published in September 2020 by Italian authors moved us: this economic study explained how to effectively manipulate women to make them participate ever more in organized breast cancer screening by mammography. The authors then congratulated themselves with confusing cynicism on the effectiveness of manipulation techniques: by withholding information from women in the invitation letters, insisting on a negative effect and a potential danger of not participating in screening, by "limiting the cognitive overload of women" (sic), it would be possible to increase participation in screening significantly.

This kind of unethical study can explain, among other things, the persistence of misinformation of women and biases in the information, which are constantly renewed, as seen in this BMC study mentioned above.

A problem common to many countries, including France

Danish authors analyzed how health authorities can subtly influence citizens to participate in cancer screening programs:

The researchers identified and analyzed several "categories of influence," i.e., several methods that can be used to push the public to undergo screening.

In a systematic table, we find that information bias is used in many countries, among which we find European countries like Italy, corroborating the finding of this BMC study, Spain, and also France, where biased information from the National Cancer Institute (INCa) is present in two of the systematic categories. See the table:

The INCa's disregard for information to women culminates with the qualification of the scientific controversy of screening as "fake news ." (Cf

Hope for improvement and consideration of overdiagnosis

A position of French sociologists on the "health projects" of the next government can be read in the article "The main topics for the next Minister of Health" published in the media 20Minutes; they are alarmed by the overdiagnosis of organized screening (in the section "Prevention").

We can read:

 "We must be wary of organized screenings; it can generate overdiagnosis, criticizes Frédéric Pierru (doctor in political science, a sociologist at the CNRS, research fellow (CR-CNRS), works at the Center for Political and Social Administrative Studies and Research (CERAPS), attached to the University of Lille). This is an individualistic, medicalized, and poor vision of prevention". He believes that it would be more effective to put resources back into maternal and child protection centers (PMI), school medicine, occupational medicine...

"Effective prevention would mean addressing diet, stress, alcohol..." says Daniel Benamouzig (sociologist, Director of Research at the CNRS, holder of the Health Chair at Sciences Po, and researcher at the Centre Sociologie des Organisations (CNRS and Sciences Po)). We know that this President is not very inclined to oppose the alcohol or pesticide lobbies. Health, particularly public health and the ecological transition, is a long-term task. It is not easy to prove oneself in five years..."

Let's hope that these far-sighted scientists are heard...

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

False-positive results in screening: tomosynthesis not effective enough

Summary Dr. C.Bour, March 28, 2022

Tomosynthesis and annual screening: half of the women experience a false alarm

A study conducted by UC Davis Health* found that half of all women screened annually with tomosynthesis** experience at least one false-positive mammogram over a decade of screening.

Reminder: A false positive occurs when a mammogram is indicated as abnormal, but there is no cancer in the breast; this is after verification by other examinations (ultrasound, MRI, sometimes breast biopsy) and after a waiting period for the results between a few days and a few weeks.

Also, to be reminded, false positives in this screening are common. While approximately 12% of 2D screening mammograms are recalled for further investigation because of a false alarm, only 4.4% of these recalls, or 0.5% overall, result in a cancer diagnosis. Thus, women are most commonly alerted and recalled for nothing, resulting in significant moral harm.

* UC Davis Medical Center is part of a major academic health center located in Sacramento, California.

** Tomosynthesis (TDS): Tomosynthesis (or 3-D mammography) is an X-ray imaging technique that decreases the effect of breast tissue overlay by reconstructing a three-dimensional image of the breast from multiple low-dose X-rays acquired at different projection angles.

The objective of the study

This study aims to answer the following question: Is there a difference between screening with digital breast tomosynthesis (3D) vs. digital mammography (2D) in the probability of false-positive results after 10 years of screening?


This is a comparative effectiveness study of 903 495 individuals undergoing 2 969 055 screening examinations.


The study found that repeated breast cancer screening with 3D mammography only modestly decreased the risk of having a false-positive result compared with standard 2D digital mammography.

The 10-year cumulative probability of at least 1 false-positive result was 6.7% lower for tomosynthesis vs. digital mammography with annual screening and 2.4% lower for tomosynthesis vs. digital mammography with biennial screening.
Therefore, the risk of false positives is lower when screening is performed every two years instead of every year, but also in the case of non-dense breasts and for older women.
However, as can be seen, the difference is modest, and the reduction in false positives with 3D mammography is only 2.4% compared to standard mammography.


"Screening technology did not have a very large impact on reducing false positives," said Michael Bissell, an epidemiologist in the UC Davis Department of Public Health Sciences and co-leader of the study, on interview.

The first author notes, "We were surprised that the new 3D technology in breast cancer screening did not significantly reduce the risk of having a false-positive result after 10 years of screening; however, the risks of false-positive results are much lower with biennial screening compared with annual screening."

Contribution of this study

An earlier study was published in JAMA Oncol in 2018 and suggested that screening with the 3D technique was associated with better specificity (i.e., fewer false positives) and an increased proportion of breast cancers with a better prognosis (smaller and node-free) across all age and breast density groups. As the false positive rate was lowered, this resulted in a decrease in the number of repeat examinations.

We had analyzed this study here (only in French) and highlighted several limitations of this study, starting with the too-small size of the sample.
The over-detection problem remained unresolved since the claimed improvement in recalling rates was made at the cost of a significant over-diagnosis.

An article in the BMJ in July 2019 by Jeanne Lenzer, a science journalist, questioned the value of adding tomosynthesis to digital mammography, which she said was unproven. According to this author, the information given to women undergoing this technique, which is on the rise in the United States, is more of a marketing argument than neutral and scientific information.

3D technology has not been integrated into the French screening program due to the uncertainties highlighted by the French High Authority for Health.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Respect patient preferences

Summary by Sophie, patient et C.Bour, MD

March 28, 2022

Patient Preferences for Outcomes Following DCIS Management Strategies: A Discrete Choice Experiment*

Chapman BM, Yang JC, Gonzalez JM, Havrilesky L, Reed SD, Hwang ES.

JCO Oncol Pract. 2021 Nov;17(11):e1639-e1648. doi: 10.1200/OP.20.00614. Epub 2021 Mar 12. PMID: 33710917.

*The Discrete Choice Method (DCM) analyzes consumer choices. Under specific behavioral hypotheses, it makes it possible to explain the trade-offs individuals make between the various attributes of a good or service.


Ductal carcinoma in situ (DCIS) is more frequent as it is routinely screened; estimates indicate that 80% of DCIS are of good prognosis and do not threaten women's health. They thus contribute significantly to the overdiagnosis of breast cancer, i.e., needless diagnoses of lesions that, if they had not been found, would not have impacted either the health or the life of women.
But almost all DCIS are treated aggressively by surgery, often combined with radiotherapy and/or hormonal therapy, depending on the management guidelines in each country. In some countries, active surveillance is proposed; in others, like France, DCIS are treated with the same aggressiveness as "true" invasive cancers.

However, there are few studies on patients' preferences for treatment options.

Here the question asked is: What trade-offs are women willing to make between side effects of treatment for ductal carcinoma in situ (DCIS) and future risk of invasive cancer?

Main result: A majority of women (71%) were willing to accept a small increase in future risk of invasive cancer for treatment scenarios that offered a reduction in treatment-related side effects.

The results of this study underscore the importance of shared decision making, weighing risks and benefits, between the patient and the caregiver managing a low-risk condition.


The term "overtreatment" has been used to characterize treatment for conditions that look like early cancer but are not destined to cause symptoms during a patient's lifetime or to be a cause of death. It has been estimated that as many as one in four patients with breast cancer detected by screening may be subject to overdiagnosis and overtreatment.
Much of this burden relates to treating ductal carcinoma in situ (DCIS or preinvasive breast cancer).
In fact, almost all CCIS are treated aggressively with surgery, radiotherapy, and/or endocrine therapy, especially in France.

The 10-year breast cancer–specific survival among women treated for DCIS is 98%-99%, implying that either current therapy is almost completely effective in eradicating breast cancer mortality or many women with DCIS would not have progressed to invasive breast cancer and thus were overtreated.

The exceptionally high breast cancer–specific survival across alternative treatment options has raised concern that in patients who have an indolent form of DCIS, treatment imposes harm without offering significant benefit.

An alternative to standard guidelines that has been proposed is the active surveillance (AS) approach, as is currently offered for many men with early prostate cancer and for women with other conditions considered high risk for breast cancer, such as atypical ductal hyperplasia, lobular carcinoma in situ, or a hereditary deleterious mutation. An AS strategy would entail close monitoring, with the aim of intervening only upon evidence of disease progression.

At the international level, four active prospective clinical trials are testing the safety and benefits of this approach: the LORD trial, which still includes patients.

(Read here:
-Since February 2019, are also accepted CIS grade II, in addition to grade I
-Since July 2020, the randomized trial has been transformed into a patient preference trial: women have the choice of the trial arm (either surveillance or conventional treatment)
-Estrogen receptor and HER2 testing has been added before patients are enrolled in the trial to rule out high-grade lesions, to make the trials even safer
-There are now 28 sites open in the Netherlands, 6 in Belgium, including a francophone site opened in Brussels :
15 sites will open in other countries, including France, to come!)

As awaiting the results of these trials, it is important to discern whether AS might be an acceptable option to some women if they were offered the opportunity to evaluate the benefits and harms of alternative management options.

In other words, would women accept other options such as AS instead of standard treatments if the benefit/risk balance was well explained to them?
To test this hypothesis, this study elicited patient preferences to quantify how women are willing to accept trade-offs among the possible management options for CCIS, including AS.

Discrete choice experiments, as in this case, are survey-based instruments used to obtain information about preferences for different aspects of goods and services of interest.
In a discrete choice experiment, participants are asked to choose between two or more experimentally designed scenarios that require trade-offs across the features (termed "attributes") of a good or a service; here, the management of DCIS; by analyzing participants' choices across questions, it is possible to estimate the relative importance of features on choices and how this orients the choices that persons then make.
In oncology scenarios, this may include trade-offs among the additional survival afforded by a proposed cancer treatment and the side effects, inconveniences, or costs associated with that treatment.


To better understand patient preferences, using a "discrete choice experiment," Hwang and coauthors recruited 194 healthy women in a screening mammography clinic.

Participants were provided with informational videos about the diagnosis and clinical significance of CCIS.
Then the women were asked to imagine that they had been diagnosed with CCIS and then choose between several management scenarios that included the option of aggressive treatments, less aggressive treatments, which also included the estimated risk of cancer and the side effects of treatments.
Different criteria were defined, such as breast appearance, severity of infection in the first year, chronic pain, hot flashes, and risk of developing or dying from breast cancer within 10 years, to create clinical pictures or "health profiles" for the different scenarios, for a more concrete representation for women depending on the choice they would make.


Not surprisingly, future risk of breast cancer and its attendant risk of mortality were the most important factors when women evaluated hypothetical management options.
However, the study found that over two-thirds of participants were willing to accept some increase in future breast cancer risk to reduce the extent of surgery or the severity and/or duration of treatment-related side effects.

In other words, a majority of women were willing to accept a small increase in a possible future risk of invasive cancer for treatment scenarios that offered reduced treatment side effects.

Conclusion and implication in real life :

This indicates that there is likely a subset of women who, when diagnosed with DCIS, would prioritize a reduction in side effect burden or extent of surgery over future breast cancer risk in certain contexts,  researchers concluded.

Most women were willing to make trade-offs between treatment-related effects and risk of invasive cancer, underscoring the need for shared decision making between patients and providers regarding treatment strategies for carcinoma in situ.

Although many discussions of management options for CCIS focus almost exclusively on future breast cancer risk and risk reduction, the results of this study confirm that women benefit if they are presented with detailed information about risks and treatment outcomes, allowing them to make a fully informed, personalized health decision.

The study confirms that treatment choice decisions for CCIS are highly sensitive to personal preferences, and that no a priori assumptions can be made about the trade-offs patients would be willing to consider when weighing the risks and side effects of treatment.

These complex considerations are fundamental to efforts to de-escalate treatments for low-risk conditions such as CCIS.

Advice for Oncologists, interview with principal author:
By Jeff Minerd, MedPage Editor March 8, 2022

In an interview, the principal author provides advice to oncologists on how to discuss CCIS treatment options with patients in a thorough and balanced manner.
Shelley Hwang, MD, on Helping Patients Make DCIS Management Decisions/Excerpts

Ductal carcinoma in situ (DCIS) is common in the United States, but there are few studies of patient preferences for treatment options. Authors :
"Estimates indicate that only 30% of DCIS may progress to invasive cancer. Nevertheless, almost all DCIS is aggressively treated with surgery, often combined with radiation and/or endocrine therapy, according to guideline-concordant care."

To better understand patient preferences, using a "discrete choice experiment, "Hwang and co-authors recruited 194 women without breast cancer from a screening mammography clinic. The women were asked to imagine they had been diagnosed with DCIS and then asked to choose among several scenarios that included aggressive and less-aggressive forms of treatment, estimation of cancer risk, and side effects.
Not surprisingly, future risk of breast cancer and mortality were the most important factors when the women evaluated hypothetical management options. However, the study found that more than two-thirds of the participants were willing to accept some increase in future breast cancer risk to reduce the extent of surgery or the severity and/or duration of treatment-related side effects.

This indicates that there is likely a subset of women who, when diagnosed with DCIS, would prioritize a reduction in side effect burden or extent of surgery over future breast cancer risk in certain contexts," the researchers concluded.

In the following interview, Hwang elaborates on the details of the study and how to discuss treatment options with patients.

Do you have any advice for how oncologists can discuss treatment options for DCIS with patients in a thorough and balanced way?

Hwang: One key step is eliciting how much knowledge a patient has about her diagnosis and its implications. I think a surgical oncologist would tend to jump right in and say, it's a cancer, we need to remove it, these are the surgical options. That's always the easiest thing for us to do, but we sometimes neglect to spend time with the patient upfront talking about the diagnosis itself and what the clinical implications are.
And when you're dealing with a disease that has no immediate clinical or life-threatening implications, and specifically for DCIS when we don't even know if it will turn into cancer even if we don't intervene surgically, I think framing the diagnosis first and making sure the patient understands the implications of the diagnosis is important.

Your study used discrete choice experiments, which were first developed for market research. Can you briefly describe how these work?

Hwang: Discrete choice experiments have been used a lot in areas such as health economics to see how people make decisions and weigh pros and cons of all the different aspects of making that decision. So say you're about to buy a house, not only do you have to consider cost but also location, how many bedrooms it has --there are many different components that go into that decision.
It's never just one driver that makes an individual decide which house to buy. There are some very emotional aspects to that too. So a discrete choice experiment tries to come up with a set of attributes that are important for making a certain kind of decision.

In this case it was a diagnosis of DCIS and the decision about how to manage it. We tried to include attributes we thought would be meaningful for patients. So postoperative pain, for instance -- that's something people wonder about and are concerned about. We included different levels of pain in the experiment. Cosmesis and side effects of treatment are also important considerations. We created different scenarios where we mixed and matched these different attributes. We presented them to patients and asked them to choose which scenario most matched their preferences. That gave us an idea of what values patients considered most important when trying to make a decision about DCIS.

I think this is something that's becoming more and more relevant. Cancer screening detects precancers such as DCIS that have no immediate clinical implications. There are no symptoms, there are no mortality implications, there's just this concern, that we're trying to prevent cancers from occurring. And I think the better we are at screening, the more we're going to find ourselves in this position, not only with cancer but also with cardiac disease and metabolic diseases, where we diagnose a condition before the patient has any symptoms.

So I think balancing the pros and cons is a lot more relevant when you're not dealing with immediate life-threatening illnesses, and learning how to talk to patients about these scenarios will be an increasingly important skill.

Your study included women without an actual diagnosis of DCIS. Do you think this limits the generalizability of your results to the general DCIS population?

Hwang:That's a really good point. We didn't feel we could do this study with women who were diagnosed with DCIS, because we didn't know what information they would come in with already. If someone somewhere along the way said to them you have cancer and it needs to come out, that could certainly affect how they viewed their choices.
To do this discrete choice experiment, we needed a group of patients that didn't have a lot of other sources of information about the disease already.

On the other hand, women in the study were coming in and presenting with an abnormality, or they were coming for a breast cancer screening, so they were  already thinking about what would happen if they did have a diagnosis. So we felt like it wasn't a stretch to use this population.

We as surgeons are taught to focus on cancer outcomes and mortality, and we should focus on those things. However, sometimes our training hasn't incorporated how to balance other things that patients care about and helping them apply these values to a treatment decision that's comfortable or preferable to them.

I've found that sometimes surgical oncologists, and oncologists in general, treat the cancer, but what we really need to do is holistically treat the patient along with the cancer. That's the take-home message of this study, underscoring how important it is to treat each person as a unique individual and someone who may not necessarily share the treating provider's belief system.

There is room in medicine to accommodate many differing views of risk and health.

For more information:

Surtraitement du CCIS du cancer du sein de stade 0

Perspective : Les risques de surdiagnostic - Nature

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

A Modeling Study on Overdiagnosis

By the Cancer Rose Collective, March 12, 2022

According to a modeling study based on data from Breast Cancer Surveillance Consortium (BCSC), about one in six to seven screened breast cancer cases is overdiagnosed.

This study first highlights that overdiagnosis in breast cancer screening is real.

Results of study

An average of 15.4% (95% CI: 9.4%-26.5%) of screened cancer cases were estimated to be overdiagnosed, reports lead author Marc D. Ryser* of Duke University in Durham, North Carolina, and colleagues.

* Ryser: Marc Daniel Ryser, Assistant Professor of Population Health Sciences. Dr. Marc Ryser is an expert in mathematical and statistical modeling. His research uses biological, clinical, and population-level data to inform and guide the early detection and prevention of cancer.

Below are the results by age group and type of cancer detected (Figure 3 and Table 3).

Beyond the average values, we can observe (Fig 3) that for all age groups, the rate of overdiagnosis can reach maximum values higher than 20%, and according to Table 3, the rate of overdiagnosis at the first screening reaches a maximum value of 28%, at 58 years 21.1%, at 66 years 25.4% and at 74 years 31.9%

In this model study, an interesting finding is that the rate of overdiagnosis increased with age and almost doubled depending on the age range analyzed: 11.5% (95% CI, 3.8%-28.3%) at the first screening at age 50 to 23.6% (95% CI, 17.7%-31.9%) at the last test at age 74.

Comparison with previous data

The authors note, "comparison of our estimates against those from other studies is not straightforward because of differences in overdiagnosis definitions and screening practices."

They conclude that their results regarding overdiagnosis are both higher than previous modeling studies (ranging from 1% to 12%, depending on the studies cited in the article) because of differences in screening practices, diagnostic practices, and modeling assumptions, but lower than other studies that have shown rates much higher than the average in this study.
For example, the Canadian screening trial estimated an overdiagnosis rate of 30% (Baines CJ, To T, Miller AB. Revised estimates of overdiagnosis from the Canadian National Breast Screening Study. Prev Med. 2016;90:66-71. [PMID: 27374944] doi:10.1016/j.ypmed.2016.06.033 ) for cancers detected by screening.
In a population-based study, Bleyer and Welch (Bleyer A, Welch HG. Effect of three decades of screening mammography on breast-cancer incidence. N Engl J Med. 2012;367:1998- 2005. [PMID: 23171096] doi:10.1056/NEJMoa1206809 ) estimated that 31% of all diagnosed breast cancer cases were overdiagnosed.

The authors conclude with the hope that their findings will join a consensus and facilitate decision-making regarding mammography screening.

Conclusions of the Editorial "Reducing the Burden of Overdiagnosis in Breast Cancer Screening and Beyond

The editorial published in conjunction with the study emphasizes the importance of informing women about what this overdiagnosis represents.
(Marcondes FO, Armstrong K. Reducing the Burden of Overdiagnosis in Breast Cancer Screening and Beyond. Ann Intern Med. 2022 March 1. doi: 10.7326/M22-0483. Epub ahead of print. PMID: 35226534.)

Authors underline: « Women who are considering having mammography screening should be counseled about the risk for unnecessary cancer treatment using this information."
Estimating that about 60% of the 280,000 cases of breast cancer diagnosed each year in the United States are discovered through mammography screening, eliminating overdiagnosis could save 25,000 women the cost and complications of unnecessary treatment.

"Substantial advances" in critical areas need to be made, according to the authors, including:
- Develop a better predictive capability to accurately identify tumors that will not progress
- Improve the accuracy of screening technologies to reduce the risk of overdiagnosis and improve the ability to detect breast cancer that has not been detected by mammography
-Implement prevention strategies to reduce the overall rate of breast cancer diagnosis, such as providing counseling on lifestyle changes and screening for genetic risk.

The authors of the editorial conclude: « Screening tests, whether for cancer or other conditions, can provide great benefit by detecting disease when it is more easily treatable. However, the risk of labeling millions of persons as having a disease without improving their outcomes is very real. For now, the key to navigating these tradeoffs remains open and effective physician–patient communication, rigorous evaluation of all proposed screening strategies, and continued investment in early detection research. We look forward to the day when making an early diagnosis always helps our patients achieve better outcomes. »

And the findings go beyond breast cancer screening.
"As screening and diagnostic testing continues to grow in clinical practice, the issue of overdiagnosis is being felt far beyond cancer screening. For some conditions, changing definitions have led patients to be labeled with a predisease state on the basis of a test result that was previously considered in the normal range. Although there are strong arguments in favor of early treatment to prevent long-term complications in many conditions, the reality is that, just as with cancer screening, there is little doubt that some patients diagnosed through a screening test would never have progressed and are likely to be receiving unnecessary treatment."

Comments and criticisms, opinion of Dr. V.Robert, statistician

1-A modeling study

The study remains a modeling study, which means that the results of a model depend on a chosen model and conditions of validity, at best unverifiable and at worst questionable. For example, the authors are obliged to consider that a breast cancer is either definitively non-evolving or inexorably evolving, with no possibility that the evolutionary status of cancer changes over time. It is not clear that things are that simple.

Another example is that the authors are obliged to build their model by considering that all progressive breast cancers evolve at the same rate and that this rate remains constant throughout the evolutionary period. In practice, there are most likely different distributions of progression rates for each type of breast cancer, and it is not clear that progression rates cannot vary over time.

2- The data on mortality from causes other than breast cancer used by the study do not seem well adapted.

On the one hand, after checking reference 25 of the study, which corresponds to the source of these data (Contribution of Breast Cancer to Overall Mortality for US Women): for a population of women aged 50 to 80 years, these data are not derived from direct measurements of mortality but from data estimated from projections (in other words, from models).

On the other hand, the data correspond to a cohort of women born in 1971. Since the median age of the women included in the study is 56 years, the cohort born in 1971 is adapted for the mortality of women included in 1971 + 56 = 2027. Or, if you prefer, the cohort adapted to have the mortality of women aged 56 in 2000-2018 should be born between 1944 and 1962. Whatever the reasoning, it is clear that the cohort considered to obtain the mortality data is too recent by at least a decade. This is not neutral since the tables in Reference 25 show a non-negligible decline in mortality over time.

3-The definition of screen-detected cancers is questionable.

Screen-detected cancers are considered to be those that meet the following two conditions: screening mammograms BI-RADS 3 to 5 + diagnosis of cancer within the next 12 months.
With criteria such as these, interval cancers are likely to be classified as screen-detected cancers (BI-RADS 3 + negative complementary examinations = screening showing no cancer; if a cancer occurs 11 months after the screening mammogram, it is an interval cancer, and yet it will be classified as a screened cancer). Even if these cases are not very frequent, they are part of the data used to adjust the parameters, and adjusting on "garbage in, garbage out" data can only give garbage results.

4- It is wrong to pretend that the study found that the overdiagnosis rate is 15%.

The reality is that the study shows that the overdiagnosis rate is somewhere between 9% and 27% (and any value within that range is possible, no more 15% than 9% or 27%).

Figure 3 from the study:

Depending on the age range, the percentage of overdiagnosis can vary up to 25% or even 32%.

Unfortunately, it is a very common mistake to take the result of a study (estimated rate from a sample) for the reality (real and unknown, rate in the population). And it is an even more common mistake to believe that the estimated rate is more likely to be close to the real rate than any other value in the confidence interval.


Based on such a study, we cannot arbitrarily consider that the debate on the frequency of overdiagnosis is closed, with a definitive frequency of 15%, as the study's authors would like.

On the other hand, the model may be interesting for answering questions about the evolution of the frequency of overdiagnosis as a function of the age of the women screened or about the evolution of the frequency of overdiagnosis as a function of the interval between two screening mammograms.    

Professor Alexandra Barrat of the University of Sydney, interviewed by Amanda Sheppeard, associate editor and reporter for Oncology Republic and The Medical Republic, said there are different methods for estimating the potential rate of overdiagnosis through breast cancer screening.
She said the study demonstrated the inevitability of overdiagnosis in screening for a number of cancers. "I think there is a need in the professional community for greater acceptance of what the evidence shows about breast cancer screening."
"We just need to recognize that this is inherent in a cancer screening program."

As a result, and beyond the evidence, according to A.Barrat, the study helped to underscore the importance of informed consent in breast cancer screening.

Conflicts of interests

Dr Ruth Etzioni - Individual investor and stock in Seno Medical

Seno’s first clinical product targets the diagnosis of breast cancer and will be used in addition to screening mammography, integrating opto-acoustics and ultrasound.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Anatomopathology, possible uncertainties

Summary by Dr. C.Bour, 18 December 2021


This case involves a 65-year-old woman who began mammograms at age 40 due to a family history of breast cancer (mother at age 80). She has already had biopsies, which revealed that she had a simple mastosis (benign condition of the breast, characterized by tension and pain in the breasts, as well as a "granular" consistency when palpating the breasts, in areas where the mammary gland is more present and dense).

A mammogram revealed two small foci of microcalcifications in one breast. A preliminary macrobiopsy was carried out, but it was unsuccessful due to difficulties in locating them. A few months later, a second macrobiopsy was performed.

The two biopsied sites revealed a carcinoma in situ (ductal carcinoma) and an "atypical hyperplasia" lesion. Due to the presence of two concomitant lesions, a complete mastectomy (complete removal) of the breast was recommended based on the pathology report.

Anatomopathology is not infallible

Breast biopsy samples can be difficult to analyze.

In a 2016 study published in the BMJ, American researchers assessed the effectiveness of 12 different strategies in reducing interpretation errors (second opinion requested for all samples, second opinion only in the case of atypia, or only in the case of the wish of the first pathologist or for first readers with less experience in breast pathology, etc...).

115 pathologists examined 240 breast biopsy specimens, one slide per case, and compared their observations to an expert consensus diagnosis.

This study revealed that pathologists who took part in the study disagreed with the expert panel's consensus about 25% of the time. Most of the disagreements were with specimens from difficult-to-interpret conditions, such as atypia, which occurs when cells appear abnormal but are not cancerous, and ductal carcinoma in situ (DCIS)

The conclusion of the study: except for invasive cancer cases where the second opinion rarely differs from the initial interpretation, ALL strategies requiring a second opinion improve diagnostic concordance and reduce misclassification rates of breast specimens from 24.7% to 18.1%, showing that variability in diagnosis is still only incompletely eliminated, especially for breast specimens with atypia.

A second opinion is thus recommended because it can mean the difference between a diagnosis of benign hyperplasia or carcinoma in situ, influencing surgical sanctions, the need for re-intervention, radiotherapy, and/or chemotherapy.

As a result, a second opinion can help patients make a therapeutic choice.

Why not propose a more systematic second reading of the biopsy?

In the case of a positive biopsy, the start of the disease is defined by this single examination of the tissue taken under the microscope (i.e., except for invasive cancer, where uncertainty is rarer) (histological diagnosis).

And it is astounding to note how, on the one hand, DCIS is considered a “stage 0” breast cancer with a very good prognosis, and how, on the other hand, the therapeutic sanctions for this DCIS and a fortiori for pre-cancerous lesions can be extremely aggressive, as aggressive as for a "true" invasive cancer.

The patient does not know the name of the person who read her biopsy; worse, she does not have the choice of the reader of her biopsy, the anatomopathologist, contrary to the choice she has for the general practitioner, the gynecologist, and even a surgeon if necessary.

This pathological anatomy report is never communicated to the patient, although it is strictly necessary and mandatory for treatment to begin. It determines the course of treatment and the therapeutic options available.

On the other hand, the pathology report is part of the patient's file and can thus be requested by the patient.

Recommendations for patients if carcinoma in situ or a borderline or atypical lesion is found.

First and foremost, don't panic; take your time. You have the following options:

1- Request that the biopsy results be sent to you physician.

2- In the event of a failure, request a complete copy of the medical file (mandatory within 8 days)

3- If you are unsuccessful, request that the Medical Council intervene to obtain it for you. You are the owner of the medical file.

4- With the result, it is legitimate to ask for a revision of the anatomopathology slides. You can even have the file re-examined by an expert (your general practitioner just has to ask for it).

5-It is also possible to ask for a second opinion from another surgeon, possibly located in another region.

The therapeutic choice can be discussed: a less aggressive intervention or even simply "careful monitoring," knowing that unfortunately in France, for the moment, very few practitioners are adept at this wait-and-see approach which is being studied in several large European trials, including the LORD trial which is still including patients.

Read here:

(-Since February 2019 are also accepted CIS grade II, in addition to grade I

-Since July 2020, the randomized trial has been transformed into a patient preference trial: women have the choice of the trial arm (either surveillance or conventional treatment)

Estrogen receptor and HER2 testing has been added before patients are enrolled in the trial to rule out high-grade lesions, to provide even greater safety in the trial

-There are now 28 sites open in the Netherlands, 6 in Belgium, and 15 sites will open in other countries (France, to come!)


An anatomopathological diagnosis should be reviewed and discussed by caregivers, rather than being accepted as a "gold standard" because it may trigger a series of aggressive treatments, the usefulness of which should be discussed with the patient.

Read more :

Website DCIS

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Explanation of the Cancer Rose Decision Support Tool

By Cancer Rose, November 27, 2021

The decision aid describes the number of cancers, the number of deaths from cancer, and the number of false alarms estimated in 2 cohorts of 2,000 women starting at age 50:

- One cohort participates in organized screening until age 59 and has 5 screening mammograms (at age 50, 52, 54, 56, and 58)

- The other cohort does not participate (0 screening mammograms).

The calculations are based on:

- French epidemiological data available (in October 2021) on the Santé Publique France website 1,2

- An assumption of 65% of the women concerned getting screened (50% through organized screening + 15% through screening on individual initiative). This hypothesis is consistent with the figures announced by INCa 3

- A hypothesis of overdiagnosis representing 20% of cancers detected in a population of screened women. This hypothesis is in the middle of the range of published values and is compatible with the range of values accepted by INCa (1 to 20%) 4

- An assumption of a 15% reduction in mortality through screening. This assumption is in the middle of the range of published values and is consistent with the range of values accepted by the INCa (15 to 21%)4

1-Estimation of the number of cancers

The epidemiological data used are presented in the table below extracted from reference 1.

click on image

The incidences shown above are expressed as the number of breast cancers per 100,000 women.

For 2.000 women, we have :

- for women aged 50-54:

285.1*2000/100000 = 5.702 cancers / 2.000 women

- for women aged 55-59:

273.1*2000/100000 = 5.462 cancers / 2,000 women

In a cohort of 2,000 women, we would observe:

5.702 cancers when the cohort is 50 years old

5.702 cancers when the cohort is 51 years old

5.702 cancers when the cohort is 52 years old

5.702 cancers when the cohort is 53 years old

5.702 cancers when the cohort is 54 years old

5.462 cancers when the cohort is 55 years old

5.462 cancers when the cohort is 56 years old

5.462 cancers when the cohort is 57 years old

5.462 cancers when the cohort is 58 years old

5.462 cancers when the cohort is 59 years old

This means a total of 55.82 cancers (rounded to 56)

This incidence, cumulated over 10 years, of 56 cancers per 2,000 women corresponds to a cohort representative of the French population. This population comprises screened women and women who are not getting screened.

In other words, the 56 cancers are the sum of cancers that affect women who get screened + cancers that affect women who do not get screened.

This can be expressed as 56 = PD*CD + PN*CN

where CD  = cumulative incidence of cancer in women who are screened

        C = cumulative incidence of cancers in women who are not screened

       PD  = proportion of women who are screened

       PN = proportion of women who are not screened

With our assumption of 65% of women being screened: PD  = 0.65 and  PN = 0.35.

We therefore have: 56 = 0,65*C+ 0,35*CN  (equation 1)

With our hypothesis of 20% overdiagnosis of cancer among women who are screened, we have: overdiagnosis = CD - C= 0,2*C       d'où   CN = 0,8*CD   (equation 2)

Combining equations 2 and 1, we obtain: 56 = 0,65*CD + 0,35*0,8*C  soit : 56 = 0,65*CD + 0,28*CD  

hence : 56 = 0,93*CD      hence :  CD = 56/0,93 = 60,22     and : CN = 0,8*CD = 0,8*60,22 = 48,18

In summary:

- the number of expected cancers in the screened cohort can be estimated at 60

- the number of expected cancers in the non-screened cohort can be estimated at 48

- the number of overdiagnoses in the screenedcohort can be estimated at 12.

2- Estimating the number of deaths

The epidemiological data used are presented in the table below taken from reference 2.

click on image

The data for women aged 50 and 60 allows us to draw Graph 1 below.

This graph suggests that survival tends to stabilize at around 70% over time. Therefore, the lethality associated with breast cancer can be estimated at approximately 30% (by lethality, we mean the proportion of women with breast cancer who will die).

To have at least 20 years of hindsight in 2018, the data come from cancers diagnosed before 1998, therefore, before the organized screening. We can therefore consider that this 30% lethality concerns unscreened women.

The number of deaths in the unscreened cohort can be estimated by applying this 30% case fatality rate to the 48 breast cancers expected in this cohort.

Thus: number of deaths among women not screened = 48*0.3 = 14.4 (rounded to 14)

Assuming a 15% reduction in mortality in the screening cohort, the number of deaths in this cohort equals 85% of the number of deaths in the unscreened cohort.

Thus: number of deaths in the screening cohort = 14.4*0.85 = 12.24 (rounded to 12)

In summary:

- The expected number of breast cancer deaths in the unscreened cohort can be estimated at 14

- the number of breast cancer deaths expected in the screening cohort can be estimated at 12

- the number of breast cancer deaths prevented by screening can be estimated at 2.

3- Sensitivity analysis

The assumption of 65% of women being screened is questionable. A sensitivity analysis, using a proportion of women being screened ranging from 50% to 90%, in 10% increments, gives the following results.

Click on image

There is slight variation in the results, particularly in overdiagnosis estimates and avoided deaths.

The assumption of a 30% case fatality in women not being screened is also questionable. A sensitivity analysis, re-running the calculation with a case fatality ranging from 10% to 50% in 5% increments, gives the results below.

click on image

The estimate of deaths is sensitive to the value chosen for the case fatality. In particular, with the problem of rounding, an underestimation of the case fatality, even a modest one (30% rather than 35%), could lead to underestimating the deaths prevented.

However, this underestimation is unlikely because the epidemiological data correspond to cancers diagnosed more than 20 years ago. The therapeutic progress made since then suggests that our estimate of 30% is more likely to be overestimated than underestimated.

4-Two other decision aids

The hypotheses used for the frequency of overdiagnosis (20%) and the reduction in mortality (15%) correspond to median hypotheses and are compatible with the ranges accepted by the INCa. However, it is interesting to look at the outcome of the decision aid based on other assumptions.

Decision aid with assumptions favorable to screening: overdiagnosis = 10% - reduction in mortality = 25%.

click on image

Decision-aid with unfavorable assumptions for screening: overdiagnosis = 40% - mortality reduction = 5%.

Click on image


  1. Defossez G, Le Guyader‑Peyrou S, Uhry Z, Grosclaude P, Colonna M, Dantony E, et al. Estimations
    nationales de l’incidence et de la mortalité par cancer en France métropolitaine entre 1990 et 2018. Volume 1 – Tumeurs solides
    . Saint‑Maurice (Fra) : Santé publique France, 2019. 372p.
  2. Molinié F, Trétarre B, Arveux P, Woronoff A-S, Lecoffre C, Lafay L et al. Survie des personnes atteintes de cancer en France métropolitaine 1989-2018 – Sein. Boulogne-Billancourt : Institut national du cancer, septembre 2020, 12 p.

5-Number of positive screenings

Source: "Indicateurs nationaux de performance du programme de dépistage du cancer du sein sur la période 2017-2018. Updated July 12, 2021. Open access on the Santé Publique France website - Last access on September 17, 2021.

During 2017-2018:

- among women aged 50 to 54, 1,131,008 screenings were performed (N01)

- In women aged 55-59, 1,043,554 screenings were performed (N01)

Calculation of what happens to 2000 women aged 50 who start screening without having had any mammograms before and who continue for 10 years, i.e. 5 screening cycles

Number of positive screenings (N05)

A cohort of 2,000 women aged 50 years and exposed to screening for 10 years:

"number of positive L1 or L2 screens before the assessment"

(N05) / number of women screened (N01) x 2,000

50 years old, Initial screening 50-54

23,310 / 150,107 x 2000 = 311 positive tests.

Remaining 2000 - 311 = 1689 women without a positive test.

52 years old, subsequent screening 50-54 years

42,351 / 526,619 x 1689 = 136 positive tests.

Remaining 1689 - 136 = 1553 women without positive test results

54 years old, subsequent screening 50-54 range

42,351 / 526,619 x 1553 = 125 positive tests.

Remain 1553 - 125 = 1428 women without positive test results

56 years old, subsequent screening 55-59

68 566 / 943 696 x 1428 = 104 positive tests

Remain 1428 - 104 = 1324 women without positive test results

58 years old, subsequent screening 55-59

68,566 / 943,696 x 1324 = 96 positive tests.

Remain 1324 - 96 = 1228 women without positive test results

Number of women with at least one positive test after 5 cycles (10 years): 2000 - 1228 = 772

This number was rounded to 770 to avoid giving a false impression of accuracy and precision.

6-Number of interval cancers

Source : Exbrayat C. et coll. "Sensibilité et spécificité du programme de dépistage organisé du cancer du sein à partir des données de cinq départements français, 2002-2006" BEH 2012 ; (35-36-37) : 404-406.

As of November 2011, there is no more comprehensive or recent French data to our knowledge.

In this study of 5 French departments from 2002 to 2006, there were:

414,432 mammograms resulting in 3082 screened cancers plus 638 interval cancers.

The percentage of interval cancers among all breast cancers is therefore :

638 / (3082 + 638) = 638 / 3720 = 17,15 %

Out of 60 cancers, we have 60 x 17.5/100 = 10.29 interval cancers, rounded to 10.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

7-Number of true positives

Since there are 60 breast cancers, of which 10 are interval cancers, the number of true positive cancers detected by mammography is 60 - 10 = 50.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

8-Number of non-overdiagnosed cancers detected

Since there are 12 overdiagnosed cancers (20% of 60), the number of true positive non-overdiagnosed cancers detected by mammography is 50 - 12 = 38.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

9-Number of false positives

Since there are 770 positive screenings, of which 50 are true positives, there are 770 - 50 = 720 false positives.

 - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

10-Number of women who had at least one biopsy


File: "tableaux de l'ensemble des indicateurs nationaux pour les années 2017 et 2018 cumulées, déclinés par rang published on July 12, 2021. Last access on November 27, 2021.

"Number of surgical biopsies or tumor resection performed (N10)

+ Number of micro or macro biopsies performed (N11)

(N10+N11) / number of women screened (N01) x 2,000

50 years old, initial screening 50-54

N10 + N11 = 1863 + 3711 = 5574

5574 / 150 107 x 2000 = 74 biopsies

Remaining 2000 - 74 = 1926 women without biopsy

52 years old, subsequent screening 50-54 years

N10 + N11 = 3335 + 6330 = 9665

9665 / 526 619 x 1926 = 35 biopsies

Remaining 1926 - 35 = 1891 women without biopsy

54 years old, subsequent screening 50-54

N10 + N11 = 3335 + 6330 = 9665

9665 / 526 619 x 1891 = 35 biopsies

Remaining 1891 - 35 = 1856 women without biopsy

56 years old, subsequent screening 55-59

N10 + N11 = 6438 + 10659 = 17097

17097 / 943 696 x 1856 = 34 biopsies

Remaining 1856 - 34 = 1822 women without biopsy

58 years old, subsequent screening 55-59

N10 + N11 = 6438 + 10659 = 17097

17097 / 943 696 x 1822 = 33 biopsies

Remaining 1822 - 33 = 1789 women without biopsy

Number of women with at least one biopsy after 5 cycles (10 years):

2000 - 1789 = 211 rounded to 210. Of these 210 biopsies, 50 resulted in cancer diagnoses, and therefore there are 210 - 50 = 160 biopsies for women who had a false positive.

Estimation of deaths due to overdiagnosis - Dr. V. Robert

Overdiagnosis is treated in the same way as progressive breast cancer. They, therefore, generate unnecessary treatments (= overtreatments). Like all treatments, overtreatment leads to side effects, some of which can be fatal. This is particularly true of radiotherapy, which can cause lung cancer or heart complications.

It is therefore indisputable that overdiagnosis and its treatment cause deaths. However, it is impossible to quantify these deaths precisely in the absence of reliable epidemiological data.

All clinical trials concluded that there is no significant difference in overall mortality (all causes) between women who are screened and those who are not screened.

This finding can be interpreted in 3 ways:

  • either there is no difference in overall mortality. In this case, the breast cancer deaths prevented by screening have to be compensated by an equivalent excess of deaths from other causes. Applied to our cohort of 2,000 screened women, this means that the 2 breast cancer deaths prevented are compensated by an excess of 2 deaths from other causes due to the 12 overdiagnoses.
  • or there is a decrease in overall mortality among screened women, which does not appear statistically significant due to a lack of power in the clinical trials. At most, this decrease in overall mortality could be equal to the decrease in breast cancer mortality. This assumes that there are no excess deaths from other causes. Applied to our cohort of 2,000 screened women, this means that there are 2 breast cancer deaths avoided and 0 deaths due to overdiagnosis.
  • or there is an increase in overall mortality in screened women, which does not appear to be statistically significant because of a lack of power in clinical trials. In this case, deaths due to overdiagnosis must outnumber breast cancer deaths prevented by screening. Applied to our cohort of 2,000 screened women, this means that the 12 overdiagnoses should account for more than 2 deaths. More than 2 deaths per 12 overdiagnoses means that overdiagnosis would cause death in more than 17% of cases. Due solely to side effects, such high case fatality seems unlikely. We do not support this hypothesis.

In summary: It is not possible to quantify precisely the deaths due to the 12 overdiagnoses, but it is likely that these deaths are between 0 and 2.

Deaths from screening and overdiagnosis - Dr. J. Doubovetzky

Randomized controlled trials have not shown a statistically significant decrease in the number of deaths due to screening. Neither have epidemiological studies (historical or geographic comparisons).

Since the introduction of screening, there has been an overall decrease in breast cancer mortality, but this is mainly attributed to improved treatment and reduction of certain risks (e.g., "preventive" hormonal treatments for menopausal disorders).

As long as it is not demonstrated that screening decreases mortality, it is normal to include the lack of mortality decrease in the assumptions.

Plausible explanatory hypotheses support this view.

There are many potentially fatal adverse effects of screening mammography and overdiagnosis. Unfortunately, these adverse events have never been thoroughly evaluated, so their mortality is not quantifiable.

These potentially fatal adverse effects include:

- The direct effects of ionizing radiation from mammography. To estimate them, we rely on indirect data such as the data from Hiroshima, the impact of the former X-ray monitoring of tuberculosis patients, or even the historical treatment of dermatological diseases by radiation. Linear mathematical models are used, which are known to be wrong.

- Suicides, cardiovascular deaths, and road accidents following the announcement of a cancer diagnosis. Their existence is demonstrated for the first two but not quantified. It is probable for the third. As far as we know, this risk is all the higher when cancer in question is perceived as serious (which is what the pro-screening campaigns contribute to). But we don't have precise figures.

- Anesthetic and infectious complications of biopsies and surgical treatments (known, poorly quantified)

- Cardiac and cancerous complications of over-treatment with radiotherapy.

- Adverse effects of treatments. For example, the undesirable effects of heart failure treatments due to overdiagnosis of radiotherapy. Or the undesirable effects of psychiatric treatments linked to anxiety and depression secondary to overdiagnosis (for example, rhythm disorders secondary to antidepressants by prolongation of the QT interval, or falls or accidents linked to benzodiazepines, partially overlapping with the previous item). These effects have been demonstrated but not quantified. They also depend on prescribing habits, which vary from country to country...

While each of these numbers may seem small, no one can assess the total impact of these adverse events. Any assessment of "I think it is a lot" or "I think it is not a lot" is purely subjective. The only true expression of this risk is "between zero and equivalent to the benefit." Or even more. Some authors have made calculations and projections that the mortality due to the adverse effects of screening and overtreatment would be greater than the gain in mortality made possible by mammography.

For example, Professor Baum estimated that for every life saved by screening, between 1 and 3 lives would be shortened by the adverse effects of overdiagnosis ([1]).

Therefore, the range we have chosen (0 to 2 deaths due to adverse effects of screening and overdiagnosis) is reasonable.

[1]Baum M "Harms from breast cancer screening outweigh benefit if death caused by treatment is included" Br Med J 2013; 346: f385. Doi: 10.1136/BMJ.f385

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Detailed information for women

This decision support tool is a simplified and practical representation of the balance between the benefits and risks of screening.

To understand the advantages and disadvantages of screening and to make an informed personal choice, the potential impact of screening on your life must be highlighted.

Not everything can be quantified in terms of mortality. Some non-fatal risks are never discussed in communications about screening, even though they will impact and alter your life.

Thus, in addition to the scientific data on mortality that we present to you visually, your personal decision about whether or not to undergo screening will be influenced by the value and weight you place on the benefits and the harms that we will discuss below.

Only a thorough presentation of all the harms and risks of screening will allow you to understand the impact of screening in "real life."

According to the importance you give to each option, you can independently decide whether or not to participate in screening based on your life experience, convictions, the vision of life, and disease.

There is no right or wrong choice, and there is your choice.

Below, we will cover the different elements that are essential for your choice:

1°- Harmful treatment side effects

Often you will hear that screened women can hope for a "less aggressive" treatment.  First and foremost, the issue is not having a "less aggressive treatment," but rather no treatment at all if it is unnecessary. Any treatment administered in the case of an unnecessary diagnosis (we'll come back to this notion) will be excessive.

Then, the "less aggressiveness" of the treatments is entirely relative, and their consequences are never mentioned as if they don't exist. However, all treatments following a breast cancer diagnosis have significant side effects, affecting the women treated in their dignity as women and their daily activities. Some of these side effects can be severe enough to require hospitalization.

First and foremost, there is surgery.

When a breast cancer diagnosis is made, you should know that either a lumpectomy or a mammectomy is performed. This means either an excision on your breast to remove the tumor, or your breast will be removed entirely (with possibly another surgery to reconstruct your breast artificially). Any surgery carries potential risks (infection, post-surgical complications, poor healing).

Contrary to some messages that claim less invasive surgeries, surgical procedures are on the rise.

Therefore, we cannot tell women that less surgery is being performed. Since the screening is being done, more breasts are being removed. 1] [2] [3] [4] [5]

Second, there are all the consequences of radiotherapy to consider.

Local effects, more or less late:

*Skin effects from superficial redness to radiodermatitis

*Lung fibrosis, which causes lung tissue to lose elasticity

*Coronary artery damage, cardiac rhythm disorders, cardiac disorders, and congestive heart failure [6].

*Radiation-induced secondary cancers in the esophagus, lung, skin, and ribs[7].

And general effects:




*Low blood cell count and blood system diseases [8]

Third, there are chemotherapies.

Chemotherapy drugs, like any effective drug, have various side effects.

-Some are very rare:

*another tumor occurrence,

*Pituitary hemorrhages (small brain gland),

*Psychotic disorders...,

-Others are rare:

*Anaphylactic reactions

*Alteration of the mood...,

-Some are more frequent:


*Paresthesias (unpleasant sensations in the extremities),


*Increased weight,

*Spinal cord compression,

*Diminished glucose tolerance,

*Heart failure, myocardial infarction,

*Bone pain,


And finally, some are very common:

*Vasomotor flushes (redness on the face),

*Diminished libido,


*Alopecia ( loss of hair),

*Dyspnea (breathing difficulties),





*Myalgia (pain in the muscles),

*Infections (sometimes severe),

*Neutropenia (low white blood cell count),

*Anemia (low red blood cell count),

*Neuropathies (neurological disorders)...

Chemotherapy is rarely a single drug, which means that you may experience a "combination" of adverse side effects depending on the proposed combinations.

2° The concrete outcome of overdiagnosis is fundamentally overtreatment

Overdiagnosis [9] is the unnecessary diagnosis of cancer that would never have endangered your life or health. It is a negative side effect of all screenings. It is difficult to quantify it. Overdiagnosis is not identifiable at the individual level. You will never know whether or not you have been diagnosed unnecessarily. There is only "one diagnosis" for both the doctor and yourself. Then any lesion will be treated.

Screening is an implicit contract with no return for the woman who participates. Accepting to participate in the screening implies that you accept all its consequences.

Indeed, when something has been detected, and it turns out to be cancer, even a small one, even a low-grade one, there is no way of knowing whether it will not progress.

Once the lesion is seen and identified as cancer by biopsy, it will be treated without any distinction being made between a cancer that would develop or a cancer that is harmless and therefore unnecessarily treated (an overdiagnosis). There is no turning back.

It should not be forgotten that even so-called "borderline" lesions are treated with the same aggressiveness.

3°The "compensation" for all of these disadvantages of screening might be a reduction in mortality or disease severity, but what is the reality?

Although screening has been in place for decades, demonstrating a reduction in mortality due to screening has proven difficult. If it existed, it would certainly be minimal.

The "lead time to diagnosis" [10] is misleading in terms of screening effectiveness because screening anticipates the "starting point" of a cancer, bringing forward the diagnosis of cancer that would have manifested itself later without screening.

This makes the cancer patient's life appear longer but not affect your longevity or life expectancy.

The more effective treatments become, the less useful the screening.

The all-cause mortality rate is never communicated, but overall mortality is not decreasing. This means that deaths from other causes may offset the meager benefit of screening. Among these other causes are the harmful and sometimes fatal effects of treatments. Finally, where is the true benefit [11]?

There is no reduction in serious, advanced cancers, precisely those we would like to see reduced by screening, indicating another failure of screening to meet its objectives.

4°-Today: screening does not guarantee the four essential expectations of women:

* There is no guarantee of dying less from breast cancer

*There is no guarantee that you will have less treatment

*There is no guarantee that your cancer will be less severe

*There is no guarantee that your life will be undisturbed, without additional stress, without a loss of quality of life, without a modification of your identity as a woman...

5° This is not a minor point: undesirable effects can occur multiple times.

A woman may experience false alarms [12] (suspicion of cancer that will not be confirmed but only after further tests and sometimes a biopsy) several times during her screening pathway.

The risk of false alarm is increased by the double reading of the mammograms, which a second radiologist will re-examine after the first reading.

Concerned that he will "miss something," the radiologist is more likely to classify an image as suspicious. A double reading increases the risk of a false alarm.

A woman may be over-diagnosed in one breast and then over-diagnosed in the other, especially since the "diagnosis" in the first breast will result in increased surveillance of the other breast.

The over-diagnosis she will face may have a transgenerational impact. This means that all of her descendants will be considered "at risk for breast cancer" and will be subjected to more frequent monitoring than usual.

6°-The psychological consequences are real and long-lasting.

A cancer diagnosis, whether it is true cancer or an overdiagnosis, or even the experience of a false alarm, causes disturbance in your biography and your perception of existence: depression, psychological disturbances related to your body image, loss of your job, loss of your social status, fear of a cancer recurrence, anxiety at the approach of each check-up, family problems, loss of income... All of this is brutal psychological suffering, and you should be aware of it.

There is also the anxiety generated while waiting for an exam, during the exam, and while waiting for the results, sometimes so intense that anxiolytics are prescribed in some cases.

7°-Finally, there is an alternative to screening: consultation in the event of symptoms.

According to studies, consulting in the presence of symptoms (such as a persistent lump) is very effective in determining a diagnosis without delay [13].


[1] Prescrire

[2] panorama de l'OCDE (partie 3)

[3] Cochrane

[4]  Etude étatsunienne

[5] Mastectomies en France







[12] The false alarm is explained in the article:



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Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Decision-aid Cochrane / Baum

This graphic is based on the Cochrane meta-analysis and M. Baum's study on the consequences of screening when treatment effects are considered.

Cochrane Data

The Cochrane Collaboration (currently the Cochrane Organization) is a non-profit organization composed of volunteer researchers from all over the world who are financially independent of the pharmaceutical industry.

This collaboration aims to systematically organize scientific information and medical research data based on properly conducted clinical trials. The scientifically validated data are summarized in an accessible way and published in the Cochrane library.

To assess the screening results and weigh the benefits and risks, researchers gathered data from all previous screening studies, which included 600,000 women – both screened and not screened. They combined the findings of all studies conducted since the 1970s to compare the benefits and harms of each situation. To make their results more concrete, they projected them onto two fictitious populations of 2 000 women in the form of a "dot chart."

Each dot represents a woman. Researchers from the Cochrane Collaboration indicate overdiagnosis (red dots), false alarms (blue dots), avoidable deaths (dark dots), and deaths (black dots) to provide a comparative picture of what happens when you have a screening versus when you don't.

Their calculations are summarized here.

English brochure is here:

Study of Professor Michael Baum, BMJ 2013

We incorporated the results of M.Baum's study, published in the BMJ journal in 2013.

Michael Baum is an Emeritus Professor of Surgery, Division of Surgery and Interventional sciences, University College London, London WC1E 6BT, United Kingdom.

According to this researcher, when treatment-related deaths are included in the mortality count, the harms of breast cancer screening outweigh the benefits.

These deaths must be considered because the expected benefit of screening (the golden dot materializing the 'life saved') is outweighed by the death due to therapeutic complications (the green dot materializing the 'life shortened' by damage caused by surgery, radiotherapy, chemotherapy, and hormone therapy).

Quote from the last paragraph of the study:

"If each of those were translated into total lives saved from all causes then I would remain content but, unfortunately, when 10 000 are screened along the way about 120 to 140 cases will be overdiagnosed with the current age group invited. Four fifths of these women would receive radiotherapy and would be at an increased risk of dying of ischaemic heart disease and lung cancer. Knowing the background risks (box 2) and multiplying these by the factors 1.27 and 1.78 gives us increases of 2% for lung cancer and 1.33% for myocardial infarction. Adding that to all cause mortality rates I crudely estimate that an additional one to three deaths might be expected from other causes for every breast cancer death avoided."

THE POSTER, download

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

Screening can only detect slow cancers


Observation of our colleague, Dr. Granger, Senology Specialist, November 2021Cancer with high invasive potential, Mrs. NP

Cancer with high invasive potential, Mrs. NP

Mrs. NP, 53 years old, consulted following her last breast assessment, classified ACR 4 due to discovering an attenuating ultrasound lesion in the left breast. There would finally be nothing suspicious after a quick micro biopsy and MRI.

Mrs. NP, wonders, however, what "truth" is hidden behind this "ACR 4" that has suddenly become "non-suspicious" and what follow-up I can provide her.

Clinically, her breasts are soft and regular, with no discernible nodules. There was no discharge or adenopathy. The mammogram reveals dense fibrosis: if the images were considered "normal," they are very uninformative due to the opacity of the tissues, and we can only note the absence of calcifications. Ultrasound confirmed the presence of multiple disseminated hypoechoic areas. At the intersection of the left external quadrants, the most important one is effectively attenuating and evokes in priority an old cystic structure, rounded and finely echogenic. Puncture under ultrasound guidance with an 18 G needle allows evacuation of a pasty serosa perfectly translucent and homogeneous on the slide: a simple gel cyst.

Conclusion: a typical gel cyst (cytology of the smear will confirm). A one-year ultrasound examination is recommended.

Monitoring was uneventful for 4 years. Then a new check-up revealed the appearance of a hypoechogenic lacuna with irregular contours about 5 mm in diameter, of very doubtful appearance, in the right supra-internal part (i.e., contralateral to the initial cystic image): its puncture under the guidance, was poor, a slide was taken for cytological analysis. This puncture will be acellular, therefore not informative: further investigations are necessary.

The 3-month check-up by palpation revealed the presence of a slightly firmer and poorly bounded area, which had not previously been noted. The hypoechogenic lacuna was verticalized on some sections (a significant sign of malignancy), absorbing, measuring 3 to 6 mm depending on the section axis, and most likely mitotic.

Conclusion: the presence of a very suspicious ultrasound lesion in the right supra-internal region which needs to be excised after ultrasound localization. Because the lesion was so small, a micro biopsy was not performed to avoid diluting it for a proper definitive histological examination (instructions from my anatomo-pathologist).

The chosen surgeon will agree to proceed "the old way" based solely on my ultrasound imaging. Histological diagnosis: infiltrating lobular carcinoma with two foci of 2 and 4 mm, separated by less than 5 mm, moderately differentiated (SBR 2), and peri-nervous sheathing. The lymph node dissection involves the removal of two massively metastatic lymph nodes. Chemotherapy, radiotherapy, and hormone therapy will be used in the treatment.

The first nine years are a "remission" phase. After that, there was a significant increase in CA 15-3, from 28 (normal value for the laboratory) to 48 U/ml in one year. A PET scan revealed a single hypermetabolic lesion of the scapula. Biopsy confirmed the lesion's metastatic nature, which is consistent with its known breast origin. A focused EBRT was carried out (inclusion in the STEREO-OS trial).

After 3 months, monitoring PET scans will reveal the appearance of new iliac, costal, and clavicular hypermetabolic foci.

This observation, which is still ongoing, raises at least two particular points for Senology practice and Screening.

1 - The initial senological evaluation classified as ACR 4 immediately triggered micro biopsy and MRI: this heavy artillery, set off and organized by the radiologist himself, without any concertation, may have "reassured" him... but not the patient, who was left without a precise diagnosis of the anomaly.

One simple procedure was needed to clarify the problem: a puncture with a fine needle under ultrasound guidance.

This overlooked technique often provides the correct answer: a simple glance at the slide with a light spot is reassuring, revealing a thin, homogeneous, and translucent layer pathognomonic of an old gel cyst. As a reminder: a simple blue needle (6/10th of external diameter, i.e., 23G) is all that is needed; the procedure is painless, much less invasive than a micro-biopsy, and twice as less expensive in the nomenclature of medical procedures).

If this puncture is performed with an 18G needle, the cyst is usually completely evacuated, depending on the degree of cyst gelation. And this immediately reassures everyone, including the patient, even before the subsequent laboratory reading.

This point concludes that our response must be graduated to avoid turning a simple, functional detail - breast cysts being extremely common during the menopausal period - into a nightmare for the patient and ruin for the health insurance system.

2 - The discovery of an abnormality in the other breast four years later did not result in such a simple diagnosis. The clinical examination and mammography were normal, as they had been the last time, but the ultrasound was suspect. The puncture proved inconclusive, necessitating close monitoring.

I would like to point out that 3 months later, the clinical status had become clear, and the imaging was more obvious. The surgery done at the same time showed a very progressive cancer since it was bifocal from the start, although small, with two massively invaded lymph nodes and phenomena of nerve sheathing, with a poor prognosis. After a few asymptomatic years, a series of bone localizations appeared quickly after the first one, confirming an all-sided evolution. The remission was only apparent; the cancer was preparing to explode.

This observation illustrates a case of cancer with high invasive potential: these cancers are always one step ahead, and we just follow their galloping tracks. They constantly put us in failure, and it is indeed against this type of cancer that a screening, even very voluntarist, is ineffective.

Screening, like all screenings, can only detect slowly progressing cancers with a good spontaneous prognosis.

Cancer Rose est un collectif de professionnels de la santé, rassemblés en association. Cancer Rose fonctionne sans publicité, sans conflit d’intérêt, sans subvention. Merci de soutenir notre action sur HelloAsso.

Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.

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